Aircraft power plant



May 30, 1939. N. c. PRICE AIRCRAFT POWER PLANT Filed Dec. 9, 1938 6 Sheets-Sheet l Er'lIIIIll!!!ll!!!lllllll iflll'Il/l I!III! I II OII I a I i I I I I l I 1 l I u l l I I r vvl INVENTOR- May 30, 1939. N. c. PRICE 2,160,281

AIRCRAFT POWER PLANT Filed Dec. 9, 1938 G SheetS-Sheet 2 uwem'osz' May 30, 1939. N. 0. PRICE AIRCRAFT POWER PLANT Filed Dec. 9, 1938 6 Sheets-Sheet 3 'IIIIIIIIIIIII/ May 30, 1939. N.. c. PRICE 2,160,281

AIRCRAFT POWER PLANT Filed Dec. 9, 1938 6 Sheets-Sheet 4 EXCHHNGER VFIPOR erzuznn-riou TURBINE 304 INVENTOR ,May 30, 1939. N. c. PRIC Z E 2,160,281 '7 AIRCRAFT POWER PLANT Filed Dec. 9, 1938 e Sheets-sheaf. 6 I

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72 v I 6 I E Patented May 30, 1939 UNITED STATES PATENT OFFICE Claims.

My invention relates to a novel method of propelling aircraft more efficiently during flight and of increasing the effective lift of the wings of the aircraft during the approach to land. In addition this technique includes a new power plant structure which is very compact and which requires no separate supporting members. The fluid flow courses associated with the thermodynamic process of the power plant are uniquely arranged to offer a minimum flow resistance, yet a maximum rate of heat transfer. Therefore the conversion of heat into power is accomplish-ed with an exceedingly light structure.

The invention is characterized in part by fuel burning apparatus which forms gases of combustion for expansion in a heat engine. The power from the engine is contributed directly or indirectly to a reduction gear for driving propulsive airscrews. In addition a second working vapor is generated by heat transmitted from the gases of combustion and is employed to operate a cluster of expansion turbines for driving the reduction gear. The exhaust vapor from the turbines is condensed in a heat disposal core. A thermally controlled atmospheric air compressor forces the cooling air through the core in accordance with the cooling requirements. The heated air issuing from the core is caused by appropriate structure to react propulsively upon the core, thereby moving the aircraft along its normal line of forward flight. The cooling air passing through the core may be diverted, subject to a control, to retard the forward motion of the aircraft and to increase the lift -of the wing.

The degree of compression of air being supplied to the combustion chamber may be so great that .inter-cooling may be necessitated in order to increase the volumetric efliciency of the induction system and to overcome detonation in the combustion chamber. If such is the case, the inter-cooling is performed together with the second working vapor condensation in the heat disposal core. The automatic regulation of the air flow through the-core compensates for variations in atmospheric temperature or density during change of operational altitude of the aircraft.

The objectives of the power plant are, first, to increase the thermodynamic efficiency of the aircraft propulsion system; second, to decrease the weight involved in the aircraft power plant installation; third, to increase the maximum speed of the aircraft; fourth, to decrease the landing speed of the aircraft; fifth, to provide a power plant installation which does not hamper the aerodynamic efficiency of the aircraft at all; sixth, to supply a power plant capable of producing great power at high altitudes as well as at low altitudes; and, seventh,-to provide a complete power installation which is quickly removable from the aircraft for overhaul or maintenance.

The structure required to accomplish these and other ends is diagrammatically illustrated in the accompanying figures. However the description so provided may be modified in detail to accomplish the same objectives. Therefore I claim the invention in its broader sense, and not merely in strict accordance with the details submitted.

Figure 1- is a perspective view of the power plant of the invention installed in the wing of a multiengine aircraft. Portions of the upper skin of the wing are broken away to show parts of the power plant and its attachments to the wing, which would otherwise be hidden. The reduction drive gear housing of the power plant is illustrated in section and a quadrant has been removed from part of the heat disposal core.

Figure 2 is a drive view of the counter-rotation ,screw propellers, the reduction drive gear assembly, and the turbine drive cluster in section along the central axis of the power plant.

Figure 3 is a phantom view of the reduction gear assembly and turbine cluster, looking along the central axis of the power plant.

Figure 4 represents a quadrant of a. cooling fin of the heat disposal core, viewed along the central axis of the power plant.

Figure 5 is a perspective view of a fragment of the heat disposal core.

Figure 6 is a view of a fragment of the heat disposal core, in section parallel to the central axis of the power plant.

Figure 7 is a perspective view of the structure which permits rapid detachment of the power plant installation from the wing of the aircraft.

Figure 8 is a perspective view 01 9. fragment of the heat disposal core adjacent to the forward end thereof.

Figure 9-=is a plan view of the power plant installation in the wing of the aircraft. Portions of the power plant and wing are shown in section along the central axis of the power plant. The-airfoil lift augmenting contrivance of the power plant is likewise illustrated.

Figure 10 is a view of the wing, in elevation and section, portraying the air flow configuration adjacent to the wing and to the lift augmenting contrivance during relatively high speed. flight of the aircraft.

Figure 11 is a view of the wing, in elevation and section, showing the air flow configuration adjacent to the wing and to the lift augmenting contrivance during an approach pf the aircraft to land.

Figure 12 is a view of one of the low pressure turbines of the turbine cluster of the power plant, in half section along the axis of rotation of the turbine wheel.

Figure 13 is a perspective view of a bucket of the turbine.

Figure 14 is a perspective view of a fragment of the wheel of the low pressure turbine.

Figure 15 is a side view of a modified form of the power plant employing closed combustion chambers. The heat disposal core and air compressing arrangements are illustrated in section alongthe central axis of the power plant.

Figure 16 is an endview of the closed combustion chambers of the power plant.

Figure 17 is a section of a modified form of the power plant, along the central axis.

Figure 18 illustrates the automatic thermal control for regulation of the heat dissipation in the core, which condenses the exhaust working fluid and cools the compressed combustion supply air.

In Figure 1 an aircraft wing is provided with a tip l3, a trailing edge 8, an upper skin 2, a lower skin 3, and a structural spar 4 between the skins for absorbing concentrated wing loads. Some power plants I of the invention project from the spar 4 in a direction opposite to that of forward flight of the aircraft. The power plants are spaced along the wing span and although each power plant is directly locked to the spar, it is quickly removable as an integral unit to facilitate substitution of a fresh power plant at the aircraft service terminal.

The power plant possesses a cylindrical shape so slender that the projection of it through the skin of the wing does not materially disrupt the continuous airfoil shape of the wing. Accordingly there is no harmful turbulence resulting from the presence of the power plant, which would reduce the efficiency of the wing and which would tend to cause buil'eting of the aircraft tail surfaces. The power plant extends with constant diameter ther to the rear it commences to decrease in diameter at a reduction gear housing It continues to decrease at a front propeller hub 30, and rear propeller hub 20, and finally vanishes to a point on the central axis of the power plant. The hub 30 bears some blades 3| of a propeller 34, and the hub 20 carries some blades 2! of a propeller 33.

Each power plant forms a source of power for driving the screw propellers and it is advantageous to further extend its usefulness, employing it as the sole support for the propellers 33 and 34 from the spar 4. Thus each component part of the power plant serves not only .as heat dissipating surface, or as a boundary surface for directing working or cooling fluids, but also as the only structure for connecting the propellers to the strength concentration of the wing. The elimination of separate supporting structures for the propellers and of separate nacelles or fairings for the power plant effects a saving of weight and space and tends to simplify the airplane.

The invention combines the power plant heat disposal core in the power plant structure. This arrangement saves weight and permits a perfect egress for the cooling air issuing from the heat disposal core. Accordingly a cylindrical core 18 having a pressure air throat ll along the power plant central axis A, and composed of some circular core fins i5 spaced by some gaps through which the air flows radially outward to the at mosphere from the throat I, constitutes the central section of the power plant.

The propeller hubs and are driven by a reduction gear assembly 39 in the housing 5|. A turbine drive cluster 49 within the housing 5| contributes power to the gear assembly. The

rearward past the trailing edge 8. Furprovided in connection with turbine cluster is shown in detail A high pressure turbine 56 having 60, a casing 61,

in Figure v2. a nozzle box some buckets 65, an extraction chamber 58, and an extraction duct 6i leading from the chamber 58 for regenerative vapor cycle feed liquid heating, is located along the central axis A of the power plant. The exhaust working vapor from the high pressure turbine, 56 is distributed radially outward along some receivers 57 to some low pressure turbines 50. The turbines 50 discharge into a supply chamber 13 of the core 18.

In Figure 3 it is shown that the cluster con-' tains six low pressure turbines grouped closely about the high pressure turbine and having axes parallel to the axis A. Some axes Dv of the low pressure turbines define the apexes of an imaginary hexagon having a center at the axis A. The turbine cluster is the most compact and lightest arrangement of turbines for expansion of working vapor through a large and therefore eiiicient ratio. Furthermore the turbine cluster fills a cylindrical space, which conforms to the shape of the remainder of the power plant facilitating compactness and strength in the power plant as a whole. The cluster arrangement makes it possible to balance the tangential thrusts of the gear drive from the turbines. Accordingly a drive pinion 52 of the high pressure turbine 56 and six drive pinions of the low pressure turbines 50 bear against three gears 53 located among the pinions. Each gear 53 meshes with the high pressure turbine pinion and with a pair of the low pressure turbine pinions. Regions of tooth contact on the gears 53 are 120 degrees apart. Some axes C of the gears 53 define the apexes of an imaginary triangle having a center at the axis A. The resultant balance of tangential gear thrusts lessens wasteful friction in the bearings supporting the gears 53 and the pinion of the high pressure'turbine. A transverse web 54 of the housing 5| aligns the gears 53 and the pinions 52 and therefore the load which must be borne by the web 54 is likewise reduced.

The rotational speed of each of the low pressure turbines 50 can be made equal to that of the high pressure turbine 56 without over-stress of the turbine wheels because the diameter of each of the low pressure turbine wheels is as small as that of the high pressure turbine wheel. The working fluid is nevertheless properly expanded because six low pressure turbines are the single high pressure turbine. Then the speed of each turbine can be made very high, about 30,000 revolutions per minute for example, and there results a saving of power plant weight. The efficiency of the turbines is improved due to the comparatively small surface for development of windage losses.

Although the speed of rotation is reduced to 7,300 revolutions per minute, for example, in the gears 53, further speed reduction is-still necessary before the power is efficiently usable in the screw propellers. It is also advantageous to accomplish torque directional differentiation and equal division of power between the propellers 33 and 34. Counter-rotation of the propellers eliminates air twist in the propeller slip-stream and reduces the propeller diameter requirements. Therefore the torque is carried from three pinions 43 extending along the axes C fom the gears 53 to three gears 44 along some axes B, and then in turn to three pinions 42 attached to the gears 44 along the axes B. The axes B define the apexes of an imaginary triangle having a center at the axis 'A.

In Figure 2 the outer surface of an internal gear 40 is borne within a bearing surface 4| of the gear housing 5|, and meshes with each of the gears 44. A tubular drive shaft 32 attaches the gear 40 to the front propeller hub 30. A tandem ball thrust bearing I33 between the shaft 32 and the housing 5| transmits the thrust of the hub 30 to the housing 5|. An external gear 28 in mesh with each of the pinions 42 is enclosed within the space provided by the hollow of the shaft 32. The torque delivered to the gear 28 is transmitted along a drive shaft 21 which passes concentrically through a bore of the hub 30 to the hub 20 of the rear propeller. The thrust and radial forces of the rear propeller are absorbed by some tandem bearing balls 26 fitted between some inter-locking shoulders 24 and 25 of the hub 30. The shoulders are ring-like extensions from the hub and have centers at the axis A, for engagement with some shoulders 23 and 29 of the hub 20.

' In aggregate the outlets of the low pressure turbines 50 define an annular shape because the low pressure turbines are grouped about the circumference of the high pressure turbine 56. Therefore the supply chamber I3 is constructed as an annular channel, and each of the heat disposal core fins I5 is shaped as an annular disc perforated with some concentric circular rows 84 'of longitudinal core channels I4 for receiving the exhaust working fluid with a minimum of turbulence, as illustrated in Figure 4.

Figure 5 shows the channels I4 passing lengthwise of the core. The channels are relatively deep in'the radial direction and narrow in the circumferential direction to permit radial flow of cooling air between.

Figure 6 illustrates that the channels I4 are composed of telescopic flanges 63 of the flns I5, which are bonded together by a controlled atmosphere copper weld causing the channels throughout the core to be imperforate and strong. Pure nickel sheet approximately ten thousandths of an inch thick is an appropriate material for the fins. Some of the fins I5 have sharp edges I'I,. while alternate fins .have some flanges I6 samped at the periphery. Theflanges I6 are telescopic, yet spaced from one another to form nozzles which face in a direction opposite to that of flight. Accordingly the heated air issuing radially from the gaps I is deflected in a rear-' ward direction by the flanges I6 and is caused to expand adiabatically by the nozzle-like action of the flanges. An effective jet reaction is produced upon the flanges I6 causing a propulsive thrust in the core I8. The heat dissipated from the core is largely recovered in the form of useful work.

Figure 1 represents a sleeve 90 joining the front end of the core I8, and in Figure '7 the attachment of the sleeve 90 to the wing spar 4 is shown in detail. Some spaced tongues 6 of the sleeve engage some spaced tongues of the spar. A removable pin I passes through the tongues 5 and 6 and locks the sleeve 90 to the spar 4.

A me hod of joining the coreI8 to the sleeve 90 is illustrated in Figure 8. The flanges of thefins I5 are indented longitudinally to form some recesses 82. Some straps I9 extend rearward from the sleeve 90 within the recesses 82. The straps transfer the bending forces involved in the support of the power plant from the sleeve 90 to the core I8, and are copper welded tothe I5.

The straps I9 define some longitudinal slots 80 within which are some up-raised fin flanges 8|. Some propulsive air jets I2 issue from the core I8.

An annular jet blanket is formed about the core I8 by the jets 12 issuing from the core and the blanket sweeps rearward along the surface of the gear housing 5| and over the hubs 30 and 20, as shown in Figure 9. Some gaps 400 are provided between the core I8 and the Wing I so that the continuity of the blanket will not be disrupted, and only the skin 2 of the wing is brought into confact with the core.

In Figure 9 the power plant derives heat from an open combustion chamber 6I2 of a vapor generator 206. A flame 209 in the chamber 6|2 propagates a combustion gas flow 201 which traverses a boiler tube 2 of the generator and drives a gas turbine 205. Finally the combustion ra ses are Wasted from a stack 208. The gas turbine drives some vapor generation accessories 204 including a feed liquid pump 2I3 which extracts feed liquid from the core I8 along a conduit 2I4. The liquid is driven from the pump 2 I3 along a feed conduit 2 I2 into the boiler tube 2II. The working vapor formed in the boiler tube is supplied to the high pressure turbine 56 along a vapor supply conduit 2 I8. The generator 206 and the turbine 205 are cylindrical in shape and-are joined end to end along the axis A adjacent to the forward end of the sleeve 90. A shaft 203 for driving an air propeller fan 20I having some blades 202 is extended from the gas turbine along the axis A. A venturi 2I0 encomasses the fan and is coaxially supported within the sleeve 90'. The venturi communicates with the pressure throat II of the heat disposal core I8. A shaft 20!! forms a drive connection between the high pressure turbine 56 and the fan 20I.

Figure 10 and the part of Figure 9 below the axis A represent the direction of the cooling air flow during normal high speed flight. The air is collected in a relatively long and narrow air scoop 500 extending from the lower skin 3. The scoop 505 is parallel and near to the trailing edge 8. Although there is a slight pressure built up in the scoop due to impact, the scoop does not result in wing-spoiling because the flow above the wing is not reduced. The air is conducted from the scoop along an air duct 50I into the venturi 2) and forced by the fan 20| into the throat II.

Figure 11 and the part of Figure 9 above the axis A illustra es the direction of the cooling air flow during approach of the aircraft to land. I In this case pumping direction of the fan 20I is reversed and as a result there exists a negative pressure in the throat I I. Therefore air is sucked rad ally inward through the gaps III of the core I8 to cool the core and is then forcedbackward along the duct 50I by the fan 20I. The heated air is expelled from the scoop 500 in a forward and downward braking jet 304. The reaction upon the wing tends to force it upward and backward. Furthermore the jet 304 acts as a jet pump, which produces a negative pressure at the trailing edge of the wing. Accordingly some air above the wing near the trailing edge 8 is drawnpast the trailing edge in a downward current 305. This latter action prevents air from below the wing'from eddying upward around the trailing edge 8 to the upper side of the wing, which is the customary cause of wing stalling.

The lift of the wing is further augmented by the addition of heat to the air passing backward along the duct 50I. In Figure 9 a bypass conduit 306 diverts some hot working vapor from the vapor supply conduit 2I8 and brings the vapor into heat exchanging relationship with the air in the duct 50I. The cooled vapor is subsequently led into the heat disposal core 18. The addition of heat to the air in the duct 50I increases the effectiveness of the jet 304 which attains a higher velocity due to the greaterexpansion resulting from the air heating. The amount of heating of the air may be regulated by a throttling valve 301 in the conduit 306.

Another cooperative mechanism for wing lift augmentation is embodied in a relatively long and narrow slot 300 in the upper skin 2 parallel to and forward of the trailing edge 8. The slot 300 has an inward opening flap 302 and is connected to the throat 'II by a duct 30I. Therefore when the approach to land is being made, the negative pressure in the throat H opens the flap 302 and causes air to be sucked from above the wing into the slot 300. This controls the air boundary layer above the skin 2 preventing air turbulence at the trailing edge from spreading forward and past the slot along the top of the wing, by consumption of the turbulent air. Some air currents 80 feeding cooling air into the core 18 likewise prevent spread of turbulence from the power plant along the upper surface of the wing.

Figure 12 illustrates the details of construction of the low pressure turbine 50 which is especially adapted to cooperate with the core 18. The wheel 66 has an origin for support adjacent to the vapor inlet end only. In this way the obstruction which an outlet end bearing would offer to the exhaust vapor is obviated. Yet the high rotative speed and the considerable axial length of the wheel predicate adequate bearing supports spaced a substantial distance apart. Accordingly the wheel 69 is made hollow. A basal bearing I13 and an end bearing I55 on the surface of a tubular spindle 64 projecting from the web 54, align the wheel 69 from within.

The bore of the spindle 64 encompasses a drive shaft 62 of the pinion 52. The shaft 62 is joined to the wheel 69 at the exhaust end by a spline I16 for transmitting torque and by a tie-bolt I10 for transmitting thrust. The turbine bearings I55 and I10 do not bear directly upon the inside of the wheel 60, but rather upon the inner surfaces of some sleeves I80 and I14 respectively, which adjacent to the bearings are spaced from the inner surface of the wheel. .The sleeves I60 and I14 are attached at one end of each to the wheel 60, but these attachments are at a substantial distance from the bearings. The spaces between the sleeves and the wheel prevent undue heat transmission from the hot wheel to the bearings because the heat must travel a considerable distance along the metal before it can reach bearings.

Oil for lubrication and cooling of the bearings is supplied under pressure at a conduit I52 in the web 54. The oil passes along a conduit I 53 into the space between the spindle 64 and the shaft 62 at the end of which it contacts the bearing I55. Some of the oil by-passes the bearing I55 through a conduit I54 in the spindle 64 and subsequently flows back along the outside of the spindle to the bearing I13. Between the sleeves I80 and I 14 is an annular vacuum space I56 defined by the inner surface of the wheel 69 and by a sleeve "I which to the of the is spaced from the wheel and bonded inner surface of the wheel at the ends sleeve I1 I. die receives Thus the oil flowing about the spinonly a limited amount of heat from the wheel 69 due to the comparatively small heat transmission through the vacuum. I

The spindle 64 must be relatively thick in order that the wheel 69 and the buckets 65 may be accurately located between an inner casing I I1 and some turbine nozzle rings 63 of the turbine. This situation requires that the metal sections in the turbine wheel be thin, so that the spindle can be accommodated within the wheel. Yet the wheel must have great strength in order to guard against bursting at high speed. Accordingly I have found that an altogether new turbine wheel construction is expedient.

It is customary to wedge or lock turbine buckets mechanically within grooves in the wheel and the presence of the buckets therefore detracts rather than contributes to the bursting strength of the wheel. In the invention each bucket is a forging, as shown in Figure 13, comprising a blade I65, a body I 66, and some lateral shoulders I61. During manufacture the buckets are assembled with the shoulders pressed beneath some rings I68, as illustrated in Figure 14. The buckets and the rings are then pressed about a tube I69, as shown in the assembled wheel of Figure 12, and are bonded to the tube I69 by a controlled atmosphere copper weld, so that the separate parts become a single piece of metal, and unlike conventional turbines the bodies I66 and the shoulders I61 of the buckets share the wheel stresses. Therefore the wheel is very strong although thin. Due to the use of over-hung bearings the Wheels may be streamlined. Thus the end of each wheel adjacent to the supply chamber 13 is relatively sharp, which permits large flow areas to be provided at the low pressure end. Large vapor expansion is readily accomplished and the exhaust working vapor leaves the last row of buckets smoothly. Leakage of working vapor from the receiver 51 to the interior of the housing 5| is prevented by a packing sleeve 48 imperforately joined to the inner casing I11 and extending between the outer surface of the sleeve I14 and the inner surface of the tube I69.

In order to reduceheat loss from the turbine casing I11 there .is provided a sleeve I 5| which surrounds and is spaced from the casing but which is imperforately bonded to the casing at the ends thereof to define an annular vacuum space I50. A working vapor extraction chamber 59 which directs bled-oil working vapor to an extraction conduit 66 for regenerative feed liquid heating is located within the space I50. The conduit 68 is shown in Figure 2.

It is also indicated in Figure 2 that the support and construction of a wheel 55 of the high pressure turbine 56 is like that of the wheels of the low pressure turbines. However in the high pressure turbine the lesser diameter of the wheel is adjacent to the high pressure region and the greater diameter is adjacent to the low pressure region. The working vapor is discharged most directly to some inlet nozzle rings I51 of the low pressure turbines with this arrangement. Frequently the bucket heights inturbines tend to be disproportionately small compared with the diameterof the wheel adjacent to the high-pressure end. In the invention there is no disproportionality because the high pressure end of the wheel can have a much smaller diameter when no main support bearing is adjacent thereto.

Figure -16 represents an internal combustion engine 6|5 which has four crank shaft axes Y spacedat ninety degree intervals and parallel to the shaft 203. Each axis Y defines the apex of a V 6|! of combustion cylinder banks 6|0. Each V extends radially outward from the axis A, so that the external shape of the engine tends to approximate a cylinder conforming to the shape of the remainder of the power plant. In the fold of each V 6|! is a combustion air induction manifold 6M. Between adjacent Vs are -some waste heat boilers 6|3. The internal combustion engine may be employed as a working fluid generator to be hereinafter described.

In Figure 15 a centrifugal air blower impeller M6 is fixed on the shaft 200 adjacent to the turbine 56. The impeller 2|6 draws compressed air from the chamber 1|, compresses it further, and forces the air longitudinally through a cylindrical air intercooler core 2|! bounding the throat '!I. The core 2|! resembles the condenser core !8 and is concentric therewith. The core 2" can be part of the condenser core 18.

The cooling air from the pressure throat 1| preferably sweeps the core 2|! prior to enterin the core 18 because the combustion air should ordinarily be cooled to a lower temperature than that of the condensate of the exhaust working vapor in the core 18. However there can be exceptions to this rule and in such case the intercooler core may surround the condenser core.

The compressed and cooled combustion air issuing from the forward end of the core 2|! is led into the manifold 6M. It is the function of the core 2|! to reduce the work of compression required for supplying the cylinders of the internal combustion engine 6|5, and to reduce the air temperature in order to suppress combustion chamber detonation.

In Figure 17 an air throttle valve 60l, which can be actuated by a lever 600, is shown in the manifold BM. Closure of the valve 60| causes the engine to cease running. The graduated control of engine power output is accomplished by a regulation of air pressure in the throat '!I through a structure to be described.

A spiral gear combination 609 on the shaft 203 drives a cross shaft 608 for the feed liquid pump 2|3. The conduit 2|2 discharges feed liquid into a helical channel 6|6 within the walls of a com bustion cylinder 6| I of the banks 6|0, The channel 6H5 cools the cylinder by vaporization of the liquid, thereby forming a working vapor which is subsequently superheated in the boiler tube 2| of the waste heat boiler 6|3. Within the cylinder 6 is an internal combustion chamber 6|2 for driving a piston 602. The piston delivers power along a connecting rod 603, a crank shaft 604, a drive gear 605, and a driven pinion 606 to the shaft 203.

In Figure 18 is shown a control for the air propeller fan blade 202. A bellows 224 containin a volatile substance, such as alcohol for example, is located in the cooling air issuing from the heat disposal core. If the bellows becomes heated beyond a predetermined temperature due to insufilciency of the cooling air flow rate compared to the rate of heat input to the heat disposal core, the alcohol vaporizes and causes the bellows to expand abruptly. The expansive efiort of the bellows is transmitted along a connecting rod 223 to a rocker arm 222 having a fulcrum 225. The motion of the rocker arm shifts a yoke 22! axially along the shaft 203. The movement of the yoke about itsaxis Z into a higher pitch angle, thereby forcing more air into the throat !I to counteract the insufiiciency vof cooling air supply.

If on the other hand the temperature of the jet 12 tends to fall below the predetermined temperature, the bellows will contract abruptly due to condensation of the alcohol within. The contraction reverses the ,described motion of the overall linkage between the bellows and the blade and forces the blade 202 into a lower pitch. Accordingly the pressure in the throat '!I is decreased and the cooling of the cores 2|! and 18 is diminished to an optimum value. A diffuser 2 5 is provided in order to convert the twist of the air leaving the blade 202 into static pressure in the throat ll.

The described control automatically maintains a substantially constant exhaust vapor pressure in the condenser core 18 and substantially constant combustion air temperature in the core 2|! although the speed of the aircraft, the density of the atmospheric air, or the attitude of the aircraft may be varying. Accordingly there is conservation of power contributed for cooling.

Of further importance is the placement of the fan 20| at the entrance to the throat II, which leads to compactness and efiiciency of the cooling system. The air flow course resulting from this arrangement is most direct, and the elimination of. interconnecting ducts between the fan and the core prevents air pressure loss.

The use of a variable pitch fan blade 202 allows an economical control of air flow to be established due to the elimination of necessity for throttling the air to regulate its flow. The blade 202 is efficient within a wide range of pitch settings and therefore throughout a considerable range of pressure rises or quantity discharges. On the other hand throttling regulation of the air flow or pressure would introduce a relatively'greatloss of power under many power plant operational conditions.

In order to produce complete reversal of flow of the cooling air during the approach of theaircraft to land when the lift of the wing is to be increased, there is provided a landing control knob 6|8 in connection with the rocker arm 222 so that the blade 202 may be forced into negative I pitch, and this causes a negative pressure'to exist in the'throat H as well as a change of air flow configuration about the wing as previously described.

The pitch of the fan blade 202 may be manually biased within the forward pitch range as well the reverse pitch range to effect a change in power plant output either greater or less than that established by the thermostatic control of the bellows 224, for variations in the pressure in the throat '!I affect the volumetric efliciency of the combustion air impeller 2|6, and in turn the power produced depends upon the amount of combustion air supplied to the combustion chambers.

I claim:

1. An aircraft power plant comprising a. propeller, a heat engine for driving said propeller, a heat disposal core having a-first end and a second end opposite to said first end thermally associated with said engine, an attachment for joining said first end to said aircraft, and means for supporting said propeller by said second end.

2. An aircraft power plant as defined in claim 1 and further characterized by said attachment consisting of a first fastening afllxed to sa d aircraft, a second fastening affixed to said first end,

and a removable pin for joining said first fastening to said second fastening.

3. An aircraft power plant comprising a propeller, a heat engine for driving said propeller, a heat disposal core thermally associated with said engine, a plurality of interstices in said core, a central recess in said core communicating with said interstices, a compressor for forcing fluid into said recess, and means for supplying relatively cool air to said compressor.

4. An aircraft power plant comprising a propeller, a heat engine for driving said propeller, a heat disposal core thermally associated with said engine, an interstice in said core having an inlet and an outlet, a compressor for forcing fluid into said inlet, means for supplying a fluid to said compressor, and said outlet facing in a direction opposed to the direction of flight of the aircraft.

5. An aircraft power plant as defined in claim 4 and further characterized by a device sensitive to the rate of heat transmission from said core to said fluid, a mechanism for adjusting the rate of discharge of said compressor, and an arrange ment for said device to regulate said mechanism.

6. An aircraft power plant as defined in claim 3 and further characterized by an induction system for conducting air for combustion from said recess to said engine.

7. An aircraft power plant as defined in claim 4 and further characterized by a wing of the aircraft, a structural member in said wing, said core being extended from said member in a direction opposed to that of flight of the aircraft, a gap between said wing and the outer surface of said core, and said outlet discharging into said gap.

8. An aircraft power plant as defined in claim 3 and further characterized by said core being composed of a plurality of annular discs, and a plurality of longitudinal tubes spacing said discs apart and in thermal contact with said discs.

9. An aircraft power plant comprising a device for generating a working fluid, an induction system for supplying said device with media for forming said fluid, an expansion chamber for converting heat into propulsive effort for propelling the aircraft, an arrangement for bringing said fluid from said device into said expansion chamber, a heat disposal core for dissipating waste heat of the power plant, an interstice in said core, a compressor, a wing of the aircraft, an expansion nozzle attached to said wing, and means for enabling said compressor to force cooling air through said interstice into said, nozzle.

10. An aircraft power plant comprising a device for generating a working fluid, an induction system for supplying said device with media for forming said fluid, an expansion chamber for converting heat into dynamic effort for propelling the aircraft, an arrangement for transferring said fluid from said device into said expansion chamber, a heat exchanger for dissipating heat of the power plant, a compressor, means for enabling said compressor to force cooling air through said exchanger, a wing of the aircraft, a first nozzle attached to said wing and facing in a first direction, a second nozzle attached to said wing and facing in a second direction, flow diverting mechanism for inducing said air to flow from said exchanger selectively into said first or into said second nozzle, and an apparatus for regulating said mechanism.

11. An aircraft power plant as defined in claim 9 and further characterized by a low pressure region adjacent to one side of said wing, a supply inlet for air to be led to said compressor, and said inlet being located adjacent to said region.

12. -A power plant as defined in claim 1 and further characterized by said core being tubular in shape, a reduction gear set supported by said second end of said core for driving said propeller, a relatively high speed shaft along the axis of said core for driving said gear set, and said heat engine for driving said shaft.

13. A power plant comprising a propeller shaft, a turbine for driving said shaft, a generating device for supplying said turbine with working vapor, a heat disposal core having a cylindrical form, an axial bore in said core, a relatively cool fluid in said bore, means for conducting exhaust working vapor from said turbine into said core directly, the axis of said core being parallel to the axis of said turbine, a plurality of interstices in said core, said interstices connecting said bore with the outside of said core, a fluid surrounding said bore, and a. mechanism for producing a pressure differential between the fluid in said bore and the fluid outside of'said core.

14. A power plant as defined in claim 13 and further characterized by a rotating wheel of said turbine, an axial hollow in said wheel, and a stationary spindle projecting into said hollow.

15. A power plant as defined in claim 13 and further characterized by a rotating wheel of said turbine, an axial hollow in said wheel, a stationary spindle projecting into said hollow, a plurality of buckets for said Wheel, a sleeve, and said wheel being constructed of said buckets and said sleeve welded together.

16. A power plant as defined in claim 3 and further characterized by a first passage in said core, a mechanism for forcing combustion air through said first passage into said engine, a second passage in said core, means for delivering coolant for use in said engine, and a conduit for transferring said coolant from said engine to said second passage.

17. A power plant as defined in claim 3 and further characterized by an inlet of said recess, an impeller of said compressor, and said impeller being located adjacent to said inlet.

18. A power plant as defined in claim 3 and further characterized by an inlet of said recess, an impeller of said compressor, a blade of said impeller, and a mechanism for adjusting the pitch of said blade.

19. A power plant as defined in claim 3 and further characterized by said core being come posed of a plurality of annular discs, a. plurality of longitudinal tubes in thermal contact with said discs and spacing said discs, and the outer edges of said discs being curled in a direction opposed to the direction of flight of the aircraft.

20. A- power plant as defined in claim 1 and further characterized by said core being tubular in shape, a reduction gear set supported by said second end of said core for driving said propeller, a relatively high speed shaft along the axis of said core, an air blower impeller mounted on said shaft, an arrangement for supplying air to said impeller, and said heat engine for driving said shaft.

NATHAN C. PRICE. 

